On rails 5.1 when trying to call an association there's a ArgumentError: wrong number of arguments

[santostiago]

I have a class Category that has many subcategories that has many subcategories_datasets through datasets.

The class datasetis the only Active Model one, while the others inherit from Active Record.

When I do category.subcategories or subcategory.category I get a ArgumentError.

Rails 5 has made some validations changes to the Active Model, and some methods now have a different number of arguments. Can you please check this? Thanks